[maliveline]

At my work we have an A20 and we mostly use extended nose collets in the back spindle and it works great. But today we are running smaller material (.125 dia.) and we realized that we couldn't use the extended nose collets because they hitting the knock-out pin assembly at the base where it screws in.

.... So, we realized that we didn't have this issue with standard collets so we put a standard collet in the back spindle. It will go through the ejection cycle in the program. but after it picks off and trys to run the next part it gives a knockout alarm now that theres a part in the back spindle. any advice would be greatly appreciated.

[danrudolph]

You can adjust the position of the knock-out at it's extended position. Remove the rear subspindle cover (the one with two screws on top and one facing the operator). There is a 4mm SHCS that is clamping on to the knock out bar.

The way I do it:

With no collet in, in MDI, input M10. Losen the SHCS mentioned above and install the collet and tighten the collet nut. Push the knock out until it interferes with the collet and back it off a bit or just so the tip of the knock out is where you want it relative to the face of the collet. Tighten the SHCS. Install covers. M11 in MDI and you're good to go.

I make this adjustment on every setup, surprised you haven't had this problem before. Although, I go from .625 extend nose collets to standard and back all the time.

[maliveline]

to be honest it wasn't really my set up I was just watching over some guys shoulder and I was trying to help him. According to him he had move the rod that connects to the knock out pin all the way to its rearward position and he was still having issues.

To be sure we are on the same page... Our a20 has a stationary knock out that does not actuate. Once the collet opens and the back spindle goes backwards the pin pokes out of the collect and ejects the part.

And the reason I have never had to mess with it is because we have always used extended nose collets on the machine with larger material so we have never had to adjust it. I have only had to worry about switching to a smaller diameter pin.

by the way what is a shcs

[danrudolph]

Oh, an A20 Type 6.

I was describing how my Type 7 is set up. Mine has an air cylinder that actuates the knock out. Apparently a different setup than yours.

SHCS = Socket Head Cap Screw

[maliveline]

ya I like the pneumatic knockout setups better but I'm not the guy with all the money to buy machines so it is what it is I guess. I'm sure those guys at my work will figure it out. I think they are going to hack up the shaft that the pin screws into to make it shorter so they can pull it back out of the way but who knows. seems like a pain in the ass if you ask me. I find it hard to believe that it would be so difficult to run .125 material on a 20mm machine and have so many issues with the knock out pin.

[maliveline]

It's almost like its not hitting the knockout pin but its still alarming. Anyone have any suggestions

[maliveline]

So I guess we are going to cut the shaft down that the knockout pin screws into so we can slide it back farther and then we are going to use really long knockout pins that will go through the extended nose collets without any interference. Unless you guys have any better ideas I appreciate any help I can get

[carmstrongls1]

WHAT ALARM ARE YOU GETTING?

[g-code_junkie]

All you have to do is make a threaded extension that fits in the front of your existing knockout pin(if it is a standard one)otherwise you can make a longer knockout pin.Either of these options will give you the clearance that you need.
good luck

[carmstrongls1]

I commonly make a boatload of different knockouts for the parts and the collet size. Sometimes I have even made "get r done" versions with a drill press, bench grinder, and a hand tap. From brass.

Doing it while the machine was running another job after years ago realizing this would be an issue from time to time.

see the rule of thumb at this link below.

Southwick & Meister - Pick-Off Collets